Power plant



' Patented May 3, 1932 KARL BAUMANN, OF 'U'RMSTON, ENGLAND, ASSIGNOR TOWESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA POWER PLANT Application filed July 18,1930, Serial No.468,915, and in Great Britain August 16, 1929.

My invention relates to steam power systems in whichthe steampassesrepeatedly through a closed cycle, being generated in a boiler atrelatively high temperature and pressure and after giving up heat in thesys- 'tem being condensed and returned as feed water to the boiler.

My invention has for its object to provide means for overcoming adisadvantage which is more particularly noticeable in systems in whichlive steam is employed for reheating purposes, as a result of whichconsiderable quantities of water may be formed at a relatively hightemperature and it is desirable to return this water to the boiler withas little reduction of the temperature or loss of pressure as possible.The disadvantage in question arises from the use of a pump to returnthis water to the boiler, there being consider- "2 0 able difficulty inpreventing leakage at the glands of the pump with consequent loss ofwater and heat energy, whilst it the glands are liquid sealed a coolingeffect is produced thereby which results in loss or degradation of heat.

According to the present-invention, however, means are provided forreturning to the boiler water condensed from the motive steam,comprising a closed receptacle which is adapted to be cooled for exampleby feed water before its entry to the boiler and which has a connectionwith the steam space of the boiler, a valve whereby said connection maybe opened or closed, a drainage connection with the boiler or with thehigh pressure side of the feed water system, a non-return valve in saiddrainage connection, and a pipe through which the said condensed watermay be conducted to the receptacle, said pipe being also provided with anon-return valve. By this means the use of a pump for the purposereferred to may be avoided, it being only necessary to open and closefrom time to time the valve which controls'the connection between thereceptacle and the steam space of the boiler. Upon opening saidvalve,steam at the temperature and pressure prevailing in the boiler ispermitted to enter the said receptacle and with the equalization of thepressure. the water in said receptacle may drain into the boiler. Uponclosing said valve the steam shut in the receptacle is cooled and maypartially condense, thereby causing a reduction in pressure in thereceptacle whereby the water condensed from the steam in the reheatingapparatus or the like may be drawn into the said receptacle. The heattaken up in cooling the steam in the receptacle is conserved in the feedwater which effects this cooling and is eventually returned to theboiler.

A steam power system is shown diagrammatically in Fig. 1 of theaccompanying drawings which illustrates by way of example a preferredarrangement of apparatus embodying the invention.

Fig. 2 shows a float control mechanism for the apparatus illustrated inFig. 1.

he power system in this example includes a steam turbine or a turbineassembly comprising a high and low pressure turbine 1 and 2 respectivelyin which the motive steam is passed through a reheater 3 at theintermediate stage of its expansion. This reheater 3 is supplied withsuperheated steam tapped off the main supply 4 from the superheater 21leading to the high pressure turbine portion 1, and condensation of thesteam takes place in thereheater. The condensed steam is drained oilinto a drainage vessel 5 which is preferably of approximately equalcapacity to a receptacle 6 which is disposed some what above the normalwater level inthe drum 7 of the boiler 20 to which drum it is connectedby a drainage connection 8. The said drainage vessel 5 and receptacle 6are connected by a pipe 9 in which is disposed a non-return valve 10adapted to permit the passage of fluid from the drainage vessel 5 to thereceptacle 6, but not in the reverse direction. A non-return valve 11 isalso provided in the drainage connection 8 which is adapted to preventthe flow of fluid therethrough from the boiler 7 to the receptacle 6.

The receptacle 6 is provided with a cooling coil 12 or the like throughwhich the feed water flows in its path in the connection 19 from thecondenser 13 to the boiler 7. The feed water may be heated progressivelyby passage through feed heaters 14, 15, 16 supplied with steampreferably tapped from the low pressure turbine portion 2, before beingutilized for cooling the receptacle 6. The

latter is connected at the top. with the steam space of the boiler drumby a pipe 17 in whicl is provided a control valve 18.

The system is operated as prevlously stated.

When the control valve 18 is opened the receptacle is filled with steam,any watertherein draining into the boiler/T. Upon will consequently dropand water from the reheater' 3 accumulating in the drainage vessel 5will be forced into the'receptacle 6. Upon again opening the' controlvalve 18 steam enters theireceptacle 6 from the boiler 7 while the waterin the receptacle drains into the boiler through the connection 8 andthe non-return valve 11.

The alternate filling and draining of the receptacle 6 maybe carried onindefinitely, the control valve 18 'beingoperated manual.- ly orautomatically asmay be preferred. In the case of automatic operation,this may take place at predetermined intervals or at intervalsdependentupon the quantity of water to be disposed of, for example by the aid; offloat mechanism or other water level responsive apparatus associatedwith the receptacle. Thefloat mechanismor other water level responsiveapparatus opens the valve 18 when the level of the condensed steam inthe re- 1 ceptacle6 rises to-a'pr-edetermined upper level, and closesthe valve when the condensate 1 level falls to .a' predetermined lowerlevel. A constructional example of float control mechanism which may beused is shown in- Fig.2. The control valve 18 is connected to a piston22 disposed in a cylinder 23. The piston 22 is biased in valve closingdirection by a spring 24 and it'is adapted to .be moved in valveopeningdirection by fluid pressure conveyed through a conduit 25 andcontrolled by a three-way valve 26. The-latter is adapted to place theconduit 25 in communication withsomesuitable source of fluid pressure,such asthe boiler 7, through a conduit 27, or to place the conduit 25 incommunication with a discharge opening 28through which the fluidpressure maybe exhausted to the atmosphere. Thethree-way valve 26. is'actuatedby a lever 29, to which there is connected a'rod 31fwhichextends into the re- .ceptacle-6. A float 32 is slidably mounted on therod 31 between two collars 33-and3 l which are fixed to the rod 31adjacent the upper andlower ends, respectively, of the receptacle 6.- V7 1 The float 32 floats on the surface of the liquidin the receptacle 6.When the liquid rection to place the conduits 27 and25 in communication.Fluidpressure is applied to the piston 22 in valve opening direction,and the control valve 18'admits steam to the receptacle 6 to permit theliquid to drain to the boiler 7. the levelpfthesliquid descends, thevalve 26 remains inthe position to which it has been moved until thelevel of the liquid approaches the bottomof the receptacle 6 when thefloat 32 abuts the collar 3 l'to move the rod 31 downwardly. The valve26 is then moved in clockwise direction to place the conduit 25 incommunication with the atmosphere through the discharge opening 28.Fluid pressure is discharged from the cylinder 23 and the spring 24moves the piston 22 in valve closing direction. The supply of steamthrough the control valve 18 is shut off and steam in the receptacle 6is condensed toidraw. in the condensate from the vessel 5 asalreadydescribed. The float control mechanism shown in Fig. 2 comprisesconventional and well known control apparatus. The specific constructionthereof forms no part of the present invention, which contemplates thefloat control mechanism merely as one element of the invention.

It may not be necessary to pass all the boiler feed waterthrough thecooling coil 12 or apparatus ofthe receptacle 16, but only a portion" ofthe available feed water may suffice in some cases, either before orafter its passage through feed water heaters 1d, 15, 16, economizers, orother apparatus. The supply of feed waterfor cooling the receptacle 6 5may flow intermittently, for example only when the. control valve18 isshut, but being by-passed when the'control valve is open.

Theireceptacle 6 and the cooling coil 12' or apparatus thereof may bedesigned as a feed I water heater proper, working intermittently inaccordance with the cycle described.

It will-be evidentthat by means such as above set forth thedisadvantages above referred to and inherent in the use of'a pump forthe purpose in question may be avoided, the loss of heat and the loss ofpower incurred in operating the control valve being exceedingly small.

- While the invention has been more particularly described above inconnection with reheaters, it will be apparent that it may be readilyapplied to other portions of a steam powersystem for the purpose ofreturning to the boiler steam condensed and collected at drain valves orother parts of the system, and where the employment ofa mechanical pumpis attended with disadvantages.

VihileI have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications, without departing from the spiritthereof, and I desire, therefore, that only such limitations'shall beplaced thereupon as are imposed by the prior art or as are specificallyset forth in the appended claims.

What I claim is: 1.' In a high pressure elastic fluid power systemarranged for returning the condensate from a motive fluid reheater tothe boiler without. a mechanical pump, the combination 7 of a boiler, aturbine comprising a high pressure portion and a low pressure portion,

I 10 means for conveying elastic fluid from the boiler to the highpressure turbine portion, a reheater for the motive fluid flowing fromthe high pressure portion to the low pressure portion, means forconveying elastic fluid from the boiler to the reheater as heatingmedium and condensing the same therein, a closed receptacle, a conduitfor conveying condensate from the heater to the receptacle and includinga check valve permitting flow toward the closed receptacle only, adrainage connection between the bottom of the receptacle and the boilerand containing a check valve permitting flow toward the boiler only, apipe between the elastic fluid space of the boiler and the closedvessel, a valve in said pipe, a cooling pipe in the closed vessel, acondenser for the low pressure turbine portion, means for conveying thecondensate from said condenser through said cooling pipe and then to theboiler, whereby when the last-mentioned valve is closed, thelastmentioned condensate condenses the steam in the closed vessel,causing the latter to draw in condensate from the reheater, and absorbsthe heat of condensation from said steam and returns it to the boiler.

2. A steam power system, according to claim 1, further including waterlevel responsive apparatus associated with said receptacle and in whichthe valve provided in the pipe connecting the said receptacle to thesteam space of the boiler is operated automatically by said water levelresponsive apparatus, the valve being closed when the level of thecondensed steam in the receptacle falls to a predetermined level andbeing opened when a predetermined upper level in the receptacle isreached.

In testimony whereof, I have hereunto sub- 59 scribed my name this 1stday of July, 1930.

KARL BAUMANN.

